interface _CS_ {
    /**
     * 判断是否为空
     * @param str 字符串
     * @returns true: 空; false: 非空;
     */
    isEmpty(str: string): boolean;
}
{
    Object.defineProperty(_CS_.prototype, 'isEmpty', {
        writable: false,
        configurable: false,
        enumerable: false,
        value: (str: string) => {
            return str === '';
        }
    });
}
